I use mostly fat free cheese for dietary reasons (I know, but it's basically just protein at that point) and can only get pre-shredded unfortunately. I do steal it so whatever.

I buy part skim in blocks and use roughly half of each for pizza because it's indistinguishable once they're cooked together. The fat free stuff doesn't melt as well as part skim... Unless you rinse it once. The water gets cloudy if you do it in a bowl, obviously a lot of the starch or whatever is separating. I mostly use a mesh strainer I have so that it doesn't become tedious to wash and drain it. But after rinsing, it melts as well as part skim if not better. Is rinsing it more of a hassle than shredding? For me, no, but if I could buy a block of fat free cheese I would. Not stocked anywhere around me, and I don't want to bother with ordering goddamn cheese online that'll get shipped with dry ice and shit...